Dust masks can help us effectively filter out harmful dust and particulate matter in the air. It is an indispensable important respiratory protection product in industrial production. So, how does the dust mask filter dust? What is its working principle?
The filter material of each layer of the dust mask is generally composed of a non-woven fabric, and the filtration function is realized by means of fiber filtration. Generally, the principle of fiber filtration dust mainly includes the following aspects: electrostatic adsorption, gravity deposition, inertial deposition, diffusion deposition effect and direct capture.
(1) Electrostatic adsorption
Most of the filter fibers of modern dust masks are electret fibers with polarized charges, and the floating particles in the air of the working environment often have positive or negative charges. These charged particles are strongly adsorbed on the electret fibers as they pass near the electret.
(2) Gravity deposition
It refers to some relatively large-sized particles passing through the mask filter material, which are deviated from the flow direction due to gravity and are deposited on the fibers during exercise.
(3) Inertial deposition
When the particles in the air pass through the mesh passage curved by the filter material, the particles with larger momentum will deviate from the flow direction due to inertia, collide with the fibers and be trapped, and be trapped due to the interaction between the molecules. This is inertial deposition.
(4) Diffusion deposition effect
Collisions between particles in the gas stream and gas molecules that are constantly undergoing thermal motion produce random Brownian motion, resulting in random movement of fine particles, which causes random collisions between the particles and the fibers. The dust particles are attracted by the gravitational forces of the fibers. Being adsorbed.
(5) Direct capture
Direct capture means that larger dust particles moving with the gas stream are trapped by the mechanical sieving of the filter material, or when the streamline is close to the fiber, the particles come into contact with the fibers and are captured by the fibers.